Reinforcement screw-bore.



1): REINFORCEMENT SCREW BORE. APPLICATION TILED NOV; 30, 1908 Patented Dec. 6, 1910.

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PAVID CRAIG, F MEI ROSE, MASSACHUSETTS, ASSIG-NOR 'IO THE DAVID CRAIG COMPANY, A CORPORATION OF MAINE.

REINFORCEMENT SCREW-BQRE.

specification of Letters Patent.

Patented Dec. 6, 1910.

Application filed November 30,1308. Serial No. 465,368.

Screw-Bores, of which the following is a the claims.

specification.

My invention relates to the reinforcement of screw bores and particularly the reinforcement of screw bores in hardened plastic material such asconcrete, clay, plaster of paris, mortar, or the like, and comprises a helically formed wire for lining the walls of the screw bore to serve as a thread to engage the thread of a screw, together with other features hereinafter fully described and pointed out in the claims.

The invention further consists of the method of forming a reinforced screw bore hereinafter described and pointed out in In the accompanyin drawings which illustrate certain embodiments of my invention,-Figure 1 is a side view of a screw together with one form of wire reinforcement for'the bore; Fig. 2 is a cross sectional View of the device shown in Fig. 1; Fig. 3 is a longitudinal section showing the device of Fig. 1 set into an object of hardened lastic material such as concrete; Fig. 4 1s a detail view of one section of the form of reinforcement employed in Figs. 1, 2 and 3 Fig. '5 is a side view of a screw together with another form'of wire reinforcement for the bore; Fig. 6 is a detail view of one section of the form of reinforcement em loyed in Fig. 5; Fig. 7 is a cross sectional view of the device shown in Fig. 5; Fig. 8 is a side view of a screw together with another form bolt or screw herein shown wire B is provided with one or more arms by which the wire is securely anchored to the material to which it is applied. These arms may be variously formed and variously disposed and I have shown herein three forms well adapted to the purpose. In Figs. 1 to 4 inclusive one end of the helical wire I extends tangentially to the helical body por-' .t1on of the wire B to form the arms shown vat b. In Figs. 5 to 7 inclusive both ends of the helioal wire extend tangentially in 0pposlte directions to form the arms I); and

in Figs. 8 and 9 the arms consist of loops 6 extending at intervals and at various anles to the helical body portion of the rein- 1 orcement.

In the form shown in Fig. 8 the-wire re,- inforcement is made in one piece extending the length of the screw. In the other figures I have shown the reinforcement as made in a plurality of sections superposed one upon the other. 1

In combining this helical wire reinforcement with an object of plastic material to form therein a reinforced screw bore, I assemble a screw and the wire reinforcement as shown in Figs. 1, 5 and 8 and then mold the concrete or other plastic material, while in its plastic condition, about the parts so assembled. Thus the helically formed wire reinforcment B is partially embedded in the plastic material C as shown in Fig. 3 and the arms projecting from B are wholly embedded in the material C, firmly anchorin the reinforcement B in the material. A ter the plastic material C has hardened I remove screw A by unscrewing it, leaving a screw bore in the hardened plastic material reinforced by the helical wire partially embedded in the walls of the bore, and forming a metallic screw thread securely anchored to the material, and capable of withstanding the strain incident to screwing another object such as a slab D tightly to the object C.

I claim:

1. A reinforcement for a screw bore comprising a wire bent to form a helix having one or more laterally projecting arms adapted to anchor said reinforcement to the material in which said bore is formed.

2. In combination with amass of hardened plastic material having a screw bore formed therein, a reinforcement for said bore comprising wire bent to form a helix partially embedded in the walls of said bore, and one or more arms projecting from and formed integral with said reinforcement and emprisin wirebent to en agethe. or thread s of a bolt or the Hie and wire arti'ally embedded in the walls of said ore and having integral arms extendin laterally away from said bore and em ded in said material.

4. In combination with amass of hardened plastic material having a screw bore formed therein, a reinforcement for'said bore comprising wire bent to form a helix partially set into the walls of said bore, and a threaded bolt or screw engaging said helical wire with its thread extending into and art way through the spaces between the 00' s of said helix, that part of said spaces between the coils of said helix not occupied b said thread bein filled with said hardene plastic materia? and arms made inte alwith said helical wire embedded in saif material whereby said reinforcement isanchored within said bore.

5. In combination with a mass of hardened plastic material having a screw bore formed therein, a reinforcement for said bore comprising wire bent to form a helix partially set into the walls of said bore, the coils of said helix being spaced apart, and a threaded bolt or screw engaging said helical wire with its thread extending into and art way through the spaces between the co' of said helix, that part of said-spaces between the coils of said helix notgoccupied lgi saidv plasthread being filled with saidharden tic material portions of said wire extendin tangentially from saidaooils and embedded in said material whereby said reinforcement is anchored within said bore.

6. In combination with an object made of hardened plastic material having a screw bore formed therein, a reinforcement for said bore comprising a plurality of wire sections superposed oneupon the other, each section bent to form a helix and partially embedded in the walls of said bore, and each formed with a bedded in said mat'eria 7 In combination with an object made of hardened plastic material having a screw bore formed therein, a reinforcement for sald bore cons1st1ng),of wire bent to form a helix partially em edded in the walls of said bore, and a plurality of arms pro'ecting' forcement in different angular directions and embedded in said material.

Signed by me at Bosto'n,Massachusetts, this 25th day of November, 1908.

.' 3 DAVID-fCRAIG.

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projecting arm emrein- 

